According to the American Medical Association, obesity is reaching epidemic proportions, affecting over 30% of American adults, or almost 70 million people. The percentage of affected adults (and children) is also climbing. In addition to the health risks presented by obesity itself, obesity increases the likelihood of a wide range of significant co-morbid health risks including cardiovascular complications (such as hypertension and hyperlipidemia), diabetes, gallbladder disease, cancer, polycystic ovary disease, pregnancy-related problems, arthritis-related problems and other orthopedic complications caused by stress on body joints.
Obesity can have several causes. Genetic, environmental and psychological factors are all believed to play a role in obesity. The mechanism for weight gain includes impaired metabolism of adipose tissue, physical inactivity (due to lifestyle or other illness), and uncontrolled appetite. Some illnesses, such as hypothyroidism, Cushing's disease and depression can also lead to obesity partly through hormonal effects, and partly through changes in appetite and lifestyle.
Regarding hormonal effects on obesity, the control of thyroid hormone secretion and adrenal gland secretion is at the level of the hypothalamus and pituitary regions of the brain. The hypothalamus secretes thyroid releasing factor which leads to release of thyroid stimulation hormone from the pituitary gland leading to increases in thyroid hormone production and release from the thyroid gland. In a similar fashion Corticotrophin releasing factor released from the hypothalamus leads to release of adrenocorticotrophic hormone that causes increased cortisol secretion from the adrenal glands causing Cushing disease.
Obesity can further be caused by certain drugs, such as steroids and some antidepressants. These effects are also thought to occur in the appetite centers in the brain.
Obesity is a common feature of neurologic diseases that appear to affect the appetite control center in the hypothalamic, pituitary and brain stem regions of the brain. Kline-Levine syndrome and sarcoidosis of the hypothalamus, for example, are associated with massive obesity.
When diet therapy proves ineffective, morbid obesity is often treated through bariatric surgery. Common bariatric surgical procedures include adjustable gastric banding and vertical banded gastroplasty (VBG).
In the noted surgical procedures, a band is surgically placed around the upper part of the stomach creating a small pouch. The pouch fills quickly when eating or drinking giving the patient the sensation of satiety.
Another popular treatment is the Roux-en-Y gastric bypass, in which a small stomach pouch is created and a section of the small intestine is attached to the pouch to allow food to bypass the lower stomach, the duodenum, and the first portion of the jejunum. This bypass reduces the amount of calories and nutrients the body absorbs.
It is also known to surgically insert a gastric balloon into the stomach to assume a portion of the volume of the stomach cavity, and, hence, reduce the available capacity of the stomach for food. This has the effect of reducing appetite and, consequently, over time (e.g., 3 months), and in combination with a suitable diet, causes weight loss.
Intragastric balloons, such as the device disclosed in U.S. Pat. No. 5,084,061, are typically designed to provide short-term therapy for moderately obese individuals requiring a reduction in weight prior to surgery, or as part of a dietary or behavioral modification program. Such devices are typically inserted into the stomach cavity in an outpatient setting (i.e., under endoscopic control), using local anesthesia and sedation.
After placement, the balloons are filled with saline solution or air from outside the cavity. Placement is typically for a period from 6 to 12 months. Removal of the balloons generally requires endoscopy.
A number of gastric balloon systems have also been employed that permit the volume of a gastric balloon to be varied over time. The purpose of facilitating volumetric changes in the gastric balloon is to provide periods of feelings of relief and well-being to the patient; not to prevent balloon accommodation and maintain appetite reduction. One such system is disclosed in U.S. Pat. No. 4,133,315 to Berman, which utilizes a flexible filling/release tube permanently coupled to the balloon. An even more invasive, surgically implanted tube design is described in U.S. Pat. No. 5,234,454 to Bangs.
In U.S. Pat. No. 5,084,061, a free floating gastric balloon is disclosed that includes a valve that can be detachable coupled to a filling tube. The device requires a physician's care and sedation for adjustment.
In addition to undesirable system complexity, each of the above-described bariatric procedures has associated risks. A significant concern with banded surgeries is a high incidence of complications, such as bleeding and/or obstruction. Though generally better tolerated than banded procedures, the Roux-en-Y gastric bypass still results in significant complications, such as vitamin and mineral deficiencies, and may lead to osteoporosis in the long-term.
Additionally, while any surgical procedure involves risks, surgical procedures on obese patients present significantly higher risks of complications and death. The obesity makes it difficult to administer anesthesia in proper doses. The surgical wounds often do not heal properly. Obese patients also face a higher risk of complications after surgery, such as deep venous thrombosis.
Severe weight loss and abnormal loss of appetite is also an equally serious condition that can lead to suffering and death. The most common example is anorexia nervosa, a condition that classically affects young women and is associated with pathologic alterations of hypothalamic and pituitary gland function. Severe anorexia can also occur in bowel conditions that cause early satiety (a feeling of fullness) or pain on eating. While anorexia is treatable with behavioral modifications, most patients require psychotropic drugs that appear effective in increasing appetite.
It would thus be desirable to provide a low-risk, unobtrusive and noninvasive method and system for treatment of eating disorders that readily prevents stomach distention and/or alternatively allows for simple, frequent and timely adjustments of the stomach cavity that is available for food intake.
It is therefore an object of the present invention to provide a method and system for treatment of eating disorders that is low-risk, unobtrusive and noninvasive.
It is another object of the invention to provide an expandable gastric device that substantially reduces or eliminates passage through the pyloric sphincter when inflated.
It is another object of the invention to provide a readily ingestible (i.e., easy to swallow) gastric device, which, when expanded, reduces the amount of food ingested to reach a feeling of fullness.
It is another object of the invention to provide an expandable, directive gastric device that is ingestible and allows food to pass through the stomach when inflated.
It is another object of the invention to provide an ingestible, inflatable gastric device having a controlled rate of inflation and, hence, expansion.
It is another object of the invention to provide an expandable, inflatable gastric device that is readily degradable (or dissoluble) by stomach contents and/or gastric fluid.
It is another object of the invention to provide an expandable, inflatable gastric device that is readily degradable (or digestible) by intestinal contents in the small and/or large intestines.
It is another object of the invention to provide an ingestible, expandable gastric device having a controlled rate of degradation.